All Sudoku Variants
8×8 · Size Variant

Sudoku 8×8

An 8×8 grid with 2×4 boxes using the digits 1–8 — a compact step up from the 6×6 board.

1 2 3 4 5 6 7 8

An example 8×8 Sudoku: digits 1–8 fill every row, column and 2×4 box.

8×8 Sudoku is an eight-by-eight grid using the digits 1–8, divided into 2×4 boxes — two cells tall and four wide. Each row, column and box must hold every digit once. It sits neatly between the gentle 6×6 and the full 9×9: bigger than a beginner grid, but still quick and forgiving.

The rule: 1–8 in every row, column and 2×4 box

Fill the grid so no digit repeats in any row, any column or any 2×4 box. The rectangular boxes — four wide, two tall — are the only structural change from Classic Sudoku. Here is a completed 8×8 grid.

1 2 3 4 5 6 7 8 5 6 7 8 1 2 3 4 2 3 4 5 6 7 8 1 6 7 8 1 2 3 4 5 3 4 5 6 7 8 1 2 7 8 1 2 3 4 5 6 4 5 6 7 8 1 2 3 8 1 2 3 4 5 6 7

A finished 8×8 grid: every row, column and 2×4 box holds 1–8 once.

Rectangular boxes shift the balance

A 2×4 box spans four columns but only two rows, so it interacts with columns and rows unevenly. A digit placed in a box clears it from four columns' worth of that box but only two rows' worth — so, as in the 6×6, column scanning tends to be a little more powerful than row scanning. Some 8×8 puzzles use 4×2 boxes (four tall, two wide) instead; the logic is identical, just rotated.

A comfortable middle size

With 64 cells and eight digits, an 8×8 is roomy enough to need real technique yet small enough to finish in a sitting. Every method from the 9×9 works here in miniature: scan a unit for a missing digit, look for a cell with only one option, and pencil candidates where a box or line is nearly full. It is an ideal grid for a solver who has outgrown the 6×6 but isn't yet reaching for Expert 9×9s.

Solving strategy

  • Scan columns first. The wide 2×4 boxes make column eliminations especially effective.
  • Complete near-full units. A row, column or box with seven of its eight digits gives the eighth for free.
  • Hunt hidden singles. With eight cells per box, a digit is often confined to a single empty cell quickly.
  • Pencil the pairs. Naked and hidden pairs still apply and resolve fast on the smaller grid.

Common mistakes

  • Expecting square boxes. The boxes are 2×4 rectangles — check the printed borders before reasoning about a box.
  • Using a 9. Only the digits 1–8 appear on an 8×8 grid.
  • Forgetting a rule. Rows, columns and boxes all still apply, exactly as on the full grid.
  • Underrating it. A hard 8×8 can still demand genuine deduction — small does not mean trivial.

Can I play it here?

Not yet — Sudoku 8×8 isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile: